NotesFAQContact Us
Search Tips
Peer reviewed Peer reviewed
Direct linkDirect link
ERIC Number: EJ859500
Record Type: Journal
Publication Date: 2009-May
Pages: 12
Abstractor: As Provided
ISSN: ISSN-0028-3932
There May Be More to Reaching than Meets the Eye: Re-Thinking Optic Ataxia
Jackson, Stephen R.; Newport, Roger; Husain, Masud; Fowlie, Jane E.; O'Donoghue, Michael; Bajaj, Nin
Neuropsychologia, v47 n6 p1397-1408 May 2009
Optic ataxia (OA) is generally thought of as a disorder of visually guided reaching movements that cannot be explained by any simple deficit in visual or motor processing. In this paper we offer a new perspective on optic ataxia; we argue that the popular characterisation of this disorder is misleading and is unrepresentative of the pattern of reaching errors typically observed in OA patients. We begin our paper by reviewing recent neurophysiological, neuropsychological, and functional brain imaging studies that have led to the proposal that the medial parietal cortex in the vicinity of the parietal-occipital junction (POJ)--the key anatomical site associated with OA--represents reaching movements in eye-centred coordinates, and that this ability is impaired in optic ataxia. Our perspective stresses the importance of the POJ and superior parietal regions of the human PPC for representing reaching movements in both extrinsic (eye-centred) and intrinsic (postural) coordinates, and proposes that it is the ability to "simultaneously" represent multiple spatial locations that must be directly compared with one another that is impaired in non-foveal OA patients. In support of this idea we review recent fMRI and behavioural studies conducted by our group that have investigated the anatomical correlates of posturally guided movements, and the movements guided by postural cues in patients presenting with optic ataxia. (Contains 5 figures.)
Elsevier. 6277 Sea Harbor Drive, Orlando, FL 32887-4800. Tel: 877-839-7126; Tel: 407-345-4020; Fax: 407-363-1354; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A